Influence of impact load on power quality of equipment power system

The modeling of induction motor as the example of impact loads in equipment power system is presented. A power quality analysis of equipment power systems when induction motors connected to the system is carried out. Influences of impact loads on terminal voltage of power supply generator are studied from three aspects such as amplitude, frequency and harmonics. Finally, in order to avoid the enormous impulsion to its starting stator current and torque brought by direct start, soft start-up circuit dominated by the bidirectional thyristor is presented and soft start-up process is simulated assisted by MATLAB/Simulink simulation which can achieve shall start current, natural transition and low harmonic distortion rate.